Expansion of g.f. A(x) satisfying Sum_{n>=0} Product_{k=1..n} (x^k + 4*A(x)) = 1 + 5*Sum_{n>=1} x^(n*(n+1)/2).

A370144

Expansion of g.f. A(x) satisfying Sum_{n>=0} Product_{k=1..n} (x^k + 4*A(x)) = 1 + 5*Sum_{n>=1} x^(n*(n+1)/2).